Fat hardening

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Fat hardening is a process in which fatty oils are solidified. The double bonds of the unsaturated fatty acid residues are thereby saturated with hydrogen - in the presence of suitable catalysts (nickel) - by hydrogenation . From the (poly) unsaturated fatty acid glycerol esters (e.g. in vegetable oils ), glycerol esters of saturated fatty acids are formed. In the process, oils are converted into solid fats.

Catalytic fat hardening with hydrogen: Above a triglyceride in an oil with a blue marked saturated fatty acid residue, a green marked monounsaturated fatty acid residue and a red marked triple unsaturated fatty acid residue. The four double bonds to be hydrogenated are each indicated by arrows. In the center of the structural formula above, the triple acylated glycerine ( marked in black ) can be seen, below the hydrogenation product (a fat), which has a higher melting point than the starting material (oil, above) with now three saturated fatty acid residues marked in blue . The four hydrated sites are also indicated by an arrow at the bottom.

From relatively inexpensive and readily available vegetable oils, products are obtained that have better technical properties than natural (solid) fats such as butter or lard . In addition to solidification (higher melting point ), better storage life and an increased smoke point are achieved.

Typical foods that contain hydrogenated fats are margarine , fats for deep-frying , many types of biscuits and packaged cakes, ready-made meals - e.g. B. breaded fish and spreads such as peanut butter . Hydrogenated fats are also used to make soap .

Fat hardening was invented by Wilhelm Normann in 1901 .

Health risks

If the hydrogenation is incomplete, glycerides of the so-called trans fatty acids can be formed as a by-product, which are considered to be a contributory cause of cardiovascular diseases . Efforts are being made to minimize the amount of undesired trans fatty acid residues produced by a clever choice of catalysts .

literature

Individual evidence

  1. ↑ Otto-Albrecht Neumüller (Ed.): Römpps Chemie-Lexikon. Volume 2: Cm-G. 8th revised and expanded edition. Franckh'sche Verlagshandlung, Stuttgart 1981, ISBN 3-440-04512-9 , pp. 1265-1270.
  2. ↑ To Philippaerts, Pierre A. Jacobs, Bert F. Sels: Does the hydrogenation of vegetable oils still have a future ?, Angew. Chem. 125 (2013) 5328-5334, doi : 10.1002 / anie.201209731 .